Small diameter endoscopic stapler

ABSTRACT

A surgical stapler is described herein which includes a shaft portion and a tool assembly supported on a distal end of the shaft portion. The too assembly includes an anvil and a cartridge body which rotatably supports a plurality of staples within notches. At least one firing cam is provided to sequentially to engage and rotate each of the staples to fire the staples from the cartridge body. In embodiments, the cartridge body includes two spaced legs which support two linear rows of staples. Each of the spaced legs of the cartridge body is supported within one of a first and a second cartridge channel. The cartridge channels are fixed to opposite sides of a pivot member which is pivotally supported at a distal end of the shaft portion between the shaft portion and the tool assembly such that translation of the first and second cartridge channels in opposite directions effects articulation of the tool assembly in relation to the shaft portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/180,578 filed Feb. 14, 2014, and the disclosures of each of theabove-identified applications are hereby incorporated by reference intheir entirety.

BACKGROUND Technical Field

The present disclosure relates to surgical staplers, and moreparticularly, to surgical staplers for laparoscopic or endoscopic use.

Background

Surgical staplers for stapling tissue during a variety of differentsurgical procedures are well known in the art. Such staplers typicallyinclude a knife to effect the simultaneous dissection and suturingtissue. When compared to applying manually threaded sutures, the use ofstaplers to suture tissue has increased the speed of the suturingprocess and thus, minimized patient trauma.

Surgical staplers suitable for use in open-type surgical procedures andlaparoscopic or endoscopic (hereinafter “endoscopic”) surgicalprocedures are well known. In an endoscopic surgical procedure, asurgical stapler is inserted through a small incision in the skin orthrough a cannula to access a surgical site. Due to the complexity ofknown surgical staplers as well as the staple size requirements or knownstaple forming apparatus, a continued need exists for small diameterstaples suitable for insertion through a small diameter cannula, e.g., a5 mm cannula.

SUMMARY

A surgical stapler is described which includes a shaft portion and atool assembly supported on a distal end of the shaft portion. The toolassembly includes an anvil and a cartridge assembly. The cartridgeassembly includes a cartridge body having at least one leg defining aplurality of notches and a plurality of staples. Each of the pluralitystaples has a backspan and a pair of curved legs connected to thebackspan. The backspan of each of the plurality of staples is rotatablysupported within a respective notch of the plurality of notches. Atleast one firing cam includes a distal end defining a cam member whichis movable within the tool assembly into sequential engagement with eachof the plurality of staples. Engagement between the cam member and astaple of the plurality of staples effects rotational movement of thestaple into the anvil member to fire the staple from the cartridge body.

In certain embodiments, each notch of the plurality of notches includesa cylindrical slot and the backspan of each of the plurality of staplesis positioned within the cylindrical slot in a snap-fit manner.

In embodiments, the cam member of the at least one firing cam includes afirst cam surface and a second cam surface. The first cam surface ispositioned to engage one curved leg of the pair of curved legs of eachof the plurality of staples and the second cam surface is positioned toengage the other curved leg of the pair of curved legs of each of theplurality of staples.

In certain embodiments, the at least one leg of the cartridge bodyincludes two spaced legs and the plurality of notches are spaced axiallyalong each of the two spaced legs. Each of the plurality of notchesrotatably supports one staple of the plurality of staples.

In embodiments, the surgical stapler includes first and second cartridgechannels having a distal end defining a U-shaped member and the twospaced legs of the cartridge body and secured within the U-shapedmembers.

In certain embodiments, the at least one firing cam includes first andsecond firing cams. Each of the cam members of the first and secondfiring cams has a U-shape and is positioned about one of the two spacedlegs of the cartridge body and within the U-shaped member of one of thefirst and second cartridge channels.

In an embodiment, the surgical stapler includes a pivot member pivotablysecured to the distal end of the shaft portion and fixedly secured toeach of the first and second cartridge channels.

In certain embodiments, the surgical stapler includes a firstarticulation link having a distal end secured to a proximal end of thefirst cartridge channel and a second articulation link secured to aproximal end of the second cartridge channel. The first and secondarticulation links is axially movable to effect axial movement of thefirst and second cartridge channels in relation to each other to pivotthe pivot member in relation to the shaft portion.

In embodiments, the surgical stapler includes a pivotal articulationmember interconnecting the first articulation link to the secondarticulation link such that movement of the first articulation link inone direction effects movement of the second articulation link in anopposite direction.

In certain embodiments, each of the pair of curved legs of the pluralityof staples is U-shaped and includes a proximal leg portion connected tothe backspan and a distal leg portion having a tapered tip.

In embodiments, the at least one leg of the cartridge body includes aplurality of dimples wherein each of the dimples is positioned to engagethe proximal leg portion of one of the plurality of staples to stabilizethe plurality of staples on the cartridge body.

In certain embodiments, the plurality of staples are supported along thecartridge body such that the proximal leg portion of each staple of theplurality of staples is positioned to guide the distal leg portion of aproximally positioned adjacent staple of the plurality of staples as theproximally positioned adjacent staple is fired from the cartridge body.

In certain embodiments, the distal-most staple of the plurality ofstaples is a dummy staple which is positioned to guide an adjacentproximal staple during firing but is not fired.

A surgical stapler is also described which includes a shaft portionhaving a proximal end and a distal end and first and second cartridgechannels extending through the shaft portion. Each of the first andsecond cartridge channels has a distal end defining a U-shaped member. Apivot member is pivotally coupled to the distal end of the shaft portionand fixedly coupled to the first cartridge channel by a first post andfixedly coupled to the second cartridge channel by a second post. A toolassembly includes an anvil and a cartridge assembly. The cartridgeassembly includes a cartridge body and a plurality of staples. Thecartridge body has a first leg supported in the U-shaped member of thefirst cartridge channel and a second leg supported in the U-shapedmember of the second cartridge channel, wherein the first and secondcartridge channels are movable axially in opposite directions to pivotthe pivot member in relation to the shaft portion and effectarticulation of the tool assembly.

In embodiments, the surgical further includes a first articulation linkhaving a distal end secured to a proximal end of the first cartridgechannel and a second articulation link secured to a proximal end of thesecond cartridge channel. The first and second articulation links areaxially movable to effect axial movement of the first and secondcartridge channels in relation to each other to pivot the pivot memberin relation to the shaft portion.

In certain embodiments, the surgical further includes a pivotalarticulation member interconnecting the first articulation link to thesecond articulation link such that movement of the first articulationlink in one direction effects movement of the second articulation linkin an opposite direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed small diameter surgicalstapler are described herein with reference to the drawings, wherein:

FIG. 1 is a side perspective view of an embodiment of the presentlydisclosed small diameter surgical stapler in an unapproximated position;

FIG. 1A is a side perspective view from the distal end of a staplerreload of the surgical stapler shown in FIG. 1;

FIG. 2 is a side perspective view from the proximal end of the surgicalstapler reload shown in FIG. 1A;

FIG. 3 is a side perspective, exploded view of the stapler reload shownin FIG. 1A;

FIG. 3A is a top, perspective view of a distal end of the upper housinghalf-section of the proximal body portion, a pivot member, and aconnecting member with parts separated;

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG.1A;

FIG. 5 is a side perspective view of a staple of the stapler reloadshown in FIG. 3;

FIG. 6 is a side perspective, exploded view of the cartridge and staplesof the stapler reload shown in FIG. 3;

FIG. 7 is an enlarged view of the indicated area of detail shown in FIG.6;

FIG. 8 is a side, cutaway view of the cartridge body supporting astaple;

FIG. 9 is a side, perspective view of a cartridge channel of the staplerreload shown in FIG. 3;

FIG. 10 is a top view of the cartridge channel shown in FIG. 9;

FIG. 11 is an enlarged view of the indicated area shown in FIG. 10;

FIG. 12 is an enlarged view of the indicated area of detail shown inFIG. 9;

FIG. 13 is a perspective, partial cross-sectional view taken alongsection line 13-13 of FIG. 12.

FIG. 14 is a side, perspective view of a firing cam of the staplerreload shown in FIG. 3;

FIG. 15 is an enlarged view of the indicated area of detail shown inFIG. 14;

FIG. 16 is a perspective, partial cross-sectional view taken alongsection line 16-16 of FIG. 15;

FIG. 17 is a side, perspective view of the cartridge assembly of thestapler reload shown in FIG. 3 supported on a distal end of the firingcams;

FIG. 18 is an enlarged view of the indicated area of detail shown inFIG. 17;

FIG. 19 is a side, perspective view of the cartridge assembly of thestapler reload shown in FIG. 3 supported on the distal ends of thecartridge channels and firing cams;

FIG. 20 is an enlarged view of the indicated area of detail shown inFIG. 19;

FIG. 21 is a top view of the stapler reload shown in FIG. 1A with thetool assembly in an unapproximated position;

FIG. 22 is a cross-sectional view taken along section line 22-22 of FIG.21;

FIG. 23 is a cross-sectional view taken along section line 23-23 of FIG.21;

FIG. 24 is an enlarged view of the indicated area of detail shown inFIG. 22;

FIG. 25 is a cross-sectional view taken along section line 25-25 of FIG.21;

FIG. 26 is a top, perspective view of the tool assembly of the staplerreload shown in FIG. 21 with the tool assembly in the approximatedposition and the firing cams advanced into engagement with aproximal-most staple of the plurality of staples;

FIG. 27 is a side, cross-sectional view of the tool assembly of thestapler reload shown in FIG. 26;

FIG. 28 is an enlarged view of the indicated area of detail shown inFIG. 27;

FIG. 29 is a side, cross-sectional view of the tool assembly of thestapler reload shown in FIG. 21 with the firing cams advanced intoengagement with a second proximal-most staple;

FIG. 30 is an enlarged view of the indicated area of detail shown inFIG. 29;

FIG. 31 is a side, cross-sectional view of the tool assembly of thestapler reload shown in FIG. 21 with the firing cams advanced todisengage the proximal-most staple of the plurality of staples from anotch in the cartridge body;

FIG. 32 is an enlarged view of the indicated area of detail shown inFIG. 31;

FIG. 33 is a cross-sectional view taken along section line 33-33 of FIG.31;

FIG. 34 is a side, perspective view of the stapler reload shown in FIG.1A in a non-articulated and unapproximated position with the proximaltube of the proximal body portion and the shaft tube of the shaftportion removed;

FIG. 35 is a top perspective view of the proximal body portion of thestapler reload with the proximal tube removed and the upper housing halfsection removed;

FIG. 36 is a top perspective view of the upper housing half section ofthe proximal body portion of the stapler reload;

FIG. 37 is a top, perspective view of the proximal body portion of thestapler reload shown in FIG. 35 with the proximal tube and the upperhousing half section removed and the articulation member rotated; and

FIG. 38 is a top view of the tool assembly of the stapler reload shownin FIG. 26 in an articulated position.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed small diameter surgical staplerwill now be described in detail with reference to the drawings whereinlike reference numerals designate identical or corresponding elements ineach of the several views. In this description, the term “proximal” isused generally to refer to the portion of the apparatus that is closerto a clinician, while the term “distal” is used generally to refer tothe portion of the apparatus that is farther from the clinician. Inaddition, the term “endoscopic” is used generally to refer toendoscopic, laparoscopic, arthroscopic, and any other surgical procedureperformed through a small incision or a cannula inserted into apatient's body.

The presently disclosed surgical stapler includes a tool assembly whichsupports a series of staples which are supported and configured to berotatably ejected from a staple cartridge into an anvil to suturetissue. The manner in which the staples are supported and ejected fromwithin the staple cartridge facilitates the use of a small diameter toolassembly which includes staples capable of suturing thicker tissues thanwould normally be associated with tool assemblies with such a smalldiameter.

FIG. 1-2 illustrate the presently disclosed surgical stapler 10 whichincludes an actuating device 12 having a handle assembly 12 a, a bodyportion 14 which extends distally from the handle portion 12, and astapler reload 100 supported on a distal end of the body portion 14. Thedistal end of the body portion 14 is adapted to releasably engage aproximal end of the reload 100 such that actuation of the actuatingdevice 12 effects operation of the reload 100. A suitable actuatingdevice is disclosed in detail in U.S. Pat. No. 5,865,361 (“361 patent”)and U.S. Pat. No. 7,143,924 (“924 patent”) which are hereby incorporatedherein in their entirety by reference. Although the presently disclosedactuating device is illustrated as a manually actuated handle assembly,it is envisioned that the reload 100 could be actuated by other knownactuating devices including robotic devices, motorized devices, and/orelectrically or mechanically driven devices.

In an alternate embodiment, the reload 100 can be fixedly attached tothe distal end of the handle assembly 12 and only a cartridge assemblyof a tool assembly can be removable and replaceable. Alternatively, aremovable and replaceable reload can also have a removable andreplaceable cartridge.

Referring also to FIG. 3, the reload 100 includes a proximal bodyportion 110, an elongated shaft portion 112 and a tool assembly 114. Theproximal body portion 110 includes an inner housing 116 defined by anupper housing half-section 116 a and a lower housing half-section 116 b.The housing half-sections 116 a and 116 b define channels which slidablyreceive a proximal drive member 118, a first articulation link 120 and asecond articulation link 122. The housing half-sections 116 a and 116 bare received within a proximal tube 125.

The first articulation link 120 is connected to the second articulationlink 122 by an articulation member 123 which will be described in detailbelow. The proximal drive member 118 supports a drive coupler 124 whichis adapted to engage a control rod (not shown) of the actuating device12 (FIG. 1) to operate the tool assembly 114 of the reload 100. Theproximal drive member 118 also supports a locking assembly 126 whichincludes a locking device 128 and a spring 130. Operation of the drivecoupler 124 and the locking assembly 126 are described in the '361patent which is incorporated herein by reference. A distal end of theproximal drive member 118 includes a hook portion 118 a. Similarly,distal ends of the first articulation link 120 and the secondarticulation link 122 include hook portions 120 a and 122 a,respectively. Each of these hook portions will be described in furtherdetail below.

The elongated shaft portion 112 includes an inner housing 134 defined byupper and lower housing half-sections 134 a and 134 b. A proximal end ofthe inner housing 134 is received within the distal end of the innerhousing 116 of the proximal body portion 110 and includes an annularrecess 135 (FIG. 25). The annular recess 135 receives a protrusion 116 cformed within the inner housing 116 to axially secure the inner housing116 of the proximal body portion 110 to the inner housing 134 of theshaft portion 112. The upper and lower housing half-sections 134 a and134 b define channels which slidably receive a pair of distal drivemembers 136 a and 136 b, a pair of firing cams 138 a and 138 b, and apair of cartridge channels 140 a and 140 b. A proximal end of each ofthe cartridge channels 140 a and 140 b defines a cutout 142 a and 142 b,respectively. The cutouts 142 a and 142 b of the cartridge channels 140a and 140 b receive the hook portions 120 a and 122 a, respectively ofthe first and second articulation links 120 and 122 such that linearmovement of the first and second articulation links 120 and 122 effectslinear movement of the cartridge channels 140 a and 140 b as will bediscussed in further detail below. A proximal end of each of the distaldrive members 136 a and 136 b includes a hook portion 144 which isengaged with the hook portion 118 a of the proximal drive member 118.Similarly, a proximal end of each of the firing cams 138 a and 138 bincludes a hook portion 146 which is also engaged with the hook portion118 a of the proximal drive member 118. Movement of the proximal drivemember 118 effects corresponding movement of the distal drive members136 a and 136 b and of the firing cams 138 a and 138 b as will bediscussed in further detail below.

The distal end of the distal drive members 136 a and 136 b are securedto a working member 150 such as by welding. In one embodiment, theworking member 150 includes an upper beam 152, a lower beam 154 and avertical strut 156 interconnecting the upper and lower beams 152 and154. A cutting edge 156 a is formed in or supported on a distal end ofthe vertical strut 156. The vertical strut 156 is movably positionedbetween the cartridge channels 140 a and 140 b, the firing cams 138 aand 138 b and the legs 188 of the cartridge body 184. The working member150 is positioned and configured to move through the tool assembly 114when the distal drive members 136 a and 136 b are advanced distallywithin the elongated shaft portion 112 as will be discussed in detailbelow.

Referring also to FIG. 3A, a pivot member 157 is secured to a distal endof the shaft housing half-sections 134 a and 134 b by upper and lowerconnecting members 160 a and 160 b. Each connecting member 160 a and 160b includes a distal end which defines an opening 162 and a proximal end164 which defines a stepped configuration. The stepped configuration ofthe proximal end 164 is received within a cutout 166 formed in thedistal end of each of the upper and lower shaft housing half-sections134 a and 134 b to axially fix the upper and lower connecting members160 a and 160 b to the upper and lower shaft housing half-sections 134 aand 134 b, respectively. The openings 162 of the connecting members 160a and 160 b each receive a respective pivot pin 170 (only one shown)formed on the upper and lower surfaces of the pivot member 156 topivotally secure the pivot member 157 to the shaft housing half-sections134 a and 134 b. The pivot member 157 also includes two transverselyextending posts 172. Each post 172 is received in an opening 210 a (FIG.13) formed in one of the cartridge channels 140 a and 140 b to securethe pivot member 156 between the cartridge channels 140 a and 140 b.

Referring to FIGS. 3-8, the tool assembly 114 includes a cartridgeassembly 180 and an anvil 182. The cartridge assembly 180 (FIG. 6)includes a cartridge body 184 and a plurality of staples that initiallyhave the shape of an open loop. In certain embodiments, the staples aregenerally U-shaped staples 186 with two prongs or legs. The cartridgebody 184 includes a tapered distal end 186 and first and second spacedlegs 188. The tapered distal end 186 of the cartridge body 184 functionsas a tissue guide and includes three proximally extending fingers 190.One of the fingers 190 is positioned on each side of each of the spacedlegs 188 with one finger 190 being positioned between the spaced legs188. Each of the fingers 190 defines a recess 192 with an adjacent leg188. The recesses 192 receive the distal ends 191 of the firing cams 138a and 138 b to secure the cartridge body 184 to the distal end of thefiring cams 138 a and 138 b.

Each of the first and second spaced legs 188 includes a series of spacednotches 196 and a pair of dimples 198 associated with each notch 196.Each of the dual staples 186 includes a backspan 200 and a pair ofspaced U-shaped curved legs or prongs 201. Each of the curved legs 201includes a proximal leg portion 202 a and a distal leg portion 202 b.One end of the proximal leg portion 202 a is connected to the backspan202 and the other end of the proximal leg portion 202 a is connected toone end of the distal leg portion 202 b. The other end of the distal legportion 202 b includes a tapered tip 202 c. The distal leg portion 202 bis curved upwardly and rearwardly towards the backspan 202.

Each notch 196 of the spaced legs 188 has a wide mouth 206 whichconverges to a cylindrical slot 204 (FIG. 8) which is configured toreceive the backspan 202 of a staple 186 in a snap-fit manner. With thebackspan 202 of a staple 186 positioned in the cylindrical slot 204 of anotch 196, the proximal leg portions 202 a of each curved leg of thestaple 186 engages one of the dimples 198 associated with each notch 196to stabilize the staple 186 on a respective leg 188 of the cartridgebody 184. In this position, the backspan 202 extends transversely acrossthe cartridge body 184 and a curved leg of each staple 186 is positionedon each side of the leg 188 of the cartridge body on which the staple186 is supported. The distal leg portions 202 b of each the staples 186engage the proximal leg 202 a of a distally positioned adjacent staple186 to further stabilize the staple 186 on the cartridge body 184 andprovide a guide surface for the staple 186 as the staple 186 is beingfired as will be discussed in further detail below.

Referring to FIGS. 9-13, each of the cartridge channels 140 a and 140 b(FIG. 3) includes a resilient body that extends from the proximal bodyportion 110 to the tool assembly 114. A distal end of each cartridgechannel 140 a and 140 b includes a U-shaped member 208 which receives aleg 188 of the cartridge body 184. Each of the U-shaped members 208defines two openings (FIG. 13) including a proximal opening 210 a and adistal opening 210 b. The proximal opening 210 a receives the post 172(FIG. 3) of the pivot member 157 to secure the cartridge assembly 180 tothe pivot member 157. The distal opening 210 b receives a pin (notshown) which extends through the opening 210 b and an opening 214 (FIG.6) in the proximal end of each of legs 188 to secure the proximal end ofthe legs 188 of cartridge body 184 to the respective cartridge channels140 a and 140 b. The distal end 191 of each U-shaped member 208 isreceived in adjacent recesses 192 formed on opposite sides of each leg188 of cartridge body 184 and is defined by a pair of cutouts 191 a anddistally extending fingers 191 b (FIG. 12). A bottom wall 193 (FIG. 13)of each cartridge channel 140 a and 140 b is w-shaped to providechannels to facilitate rotation of the staples 186 within the cartridgechannels 140 a and 140 b.

Referring to FIGS. 14-16, the distal end 220 of each firing cam 138 aand 138 b defines a cam member 222. The cam member 222 has a wavy,curved shape. In certain embodiments, the cam member includes a portionfor moving the staple into engagement with an anvil pocket and at leastone portion for forming the staple into a closed configuration. In theembodiment shown, the cam member has a portion for partially forming thestaple, and a portion for deforming the staple into its finalconfiguration.

The cam member 222 has first and second cam surfaces 222 a and 222 b.Each cam member 222 is U-shaped and defines a channel 224 which receivesa respective one of legs 188 (FIG. 6) of the cartridge body 184 suchthat each cam member 222 is slidable along the leg 188 of the cartridgebody 184 into engagement with staples 186. Each of the cam surfaces 222a and 222 b is curved and defines a first curved surface 226 and asecond curved surface 228 which are interconnected by a plateau 230. Thecam surfaces 222 a and 222 b increase in height from a distal end ofeach of the cam surface 222 a and 222 b towards a proximal end of thecam surfaces 222 a and 222 b. The first curved surface 226 is configuredto initiate deformation of a leg 201 of a staple 186 and the secondcurved surface 228 is configured to complete deformation of the leg 201of a staple and to disengage the leg from the cylindrical opening of anotch 196 of the cartridge body 184.

Referring also to FIGS. 17-20, when the cartridge channels 140 a and 140b are positioned about the legs 188 of the cartridge body 184 andsecured to the cartridge body 184, a space “s” (FIG. 33) is definedbetween sidewalls of the legs 188 and inner walls of the cartridgechannels 140 a and 140 b. A cam surface 222 a, 222 b formed on thedistal end 220 of each of the firing cams 138 a and 138 b is slidablysupported in the space “s” defined between the legs 188 and thecartridge channels 140 a and 140 b. When the firing cams 138 a and 138 bare advanced distally from a retracted position to an advanced position,the cam surfaces 222 a and 222 b are moved between the legs 188 and thecartridge channels 140 a and 140 b into sequential contact with thestaples 186 to urge the staples 186 from the cartridge body 184 into thestaple forming depressions 182 a (FIG. 22) of the anvil 182 as will bediscussed in further detail below.

Referring to FIGS. 3 and 21-25, the anvil 182 defines an elongated slot252 and on elongated cavity 254. The vertical strut 156 passes throughthe elongated slot 252 such that the upper beam 152 is slidablypositioned in the elongated cavity 254 of the anvil 182. A proximal endof the anvil 182 defines a tapered cam surface 256 which is positionedin engagement with a distal end of the upper beam 152 of the workingmember 150 when the anvil 182 is pivoted to an open position as shown inFIG. 22. The lower beam 154 is positioned to move along the bottomsurface of the cartridge channels 140 a and 140 b.

Referring briefly again to FIG. 3, the reload 100 includes a lockingmember 300 which is rotatably supported about a proximal end of theproximal body portion 110. The locking member 300 is movable from afirst position (FIG. 25) in which the locking member 300 blocks distaladvancement of the proximal drive member 118 to a second position inwhich the locking member does not block movement of the proximal drivemember 118. U.S. Pat. No. 7,143,924 describes the locking member 300 andits method of operation in detail and is incorporated herein byreference in its entirety.

Referring again to FIGS. 21-25, when the proximal drive member 118 (FIG.25) is in a retracted position, the distal drive members 136 a and 136 band the firing cam 138 a and 138 b are also in a retracted position. Inthe retracted position of the distal drive members 136 a and 136 b, thedistal end of the upper beam 152 of the working member 150 is positionedin engagement with the tapered cam surface 256 of the anvil 182 to urgethe anvil 182 to an open position spaced from the cartridge body 184(FIG. 22). In the retracted position of the firing cams 138 a and 138 b,the cam surfaces 222 a and 222 b of each of the firing cams 138 a and138 b is positioned proximally of the staples 186 (FIG. 24) such that aproximal end 259 (FIG. 18) of cam surface 222 b of each firing cam 138 aand 138 b is in abutment with a shoulder 260 (FIG. 6) of a respectiveleg 188 of the cartridge body 184.

Referring to FIGS. 26-28, when the proximal drive member 118 is advancedby operation of the actuating device 12 (FIG. 1), the upper beam 152 ofthe working member 150 is moved over the tapered cam surface 256 (FIG.27) of the anvil 182 to pivot the anvil 182 to an approximated position(FIG. 26).

Referring also to FIGS. 29-33, continued advancement of the proximaldrive member 118 (FIG. 25), moves cam surfaces 222 a and 222 b (only 222b is shown in FIGS. 29-33) of each of the firing cams 138 a and 138 bsequentially into contact with the staples 186. More particularly, whenthe firing cams 138 a and 138 b are advanced about legs 188 of cartridgebody 184, the cam surfaces 222 a and 222 b sequentially engage theproximal leg portions 202 a of the staples 186 to rotate or pivot thestaples 186 about the backspan 202 within the cylindrical slot 208 of arespective notch 196. As the proximal leg portion 202 a of each staple186 moves along the first curved cam surface 226 of cam surfaces 222 aand 222 b, each staple 186 is pivoted or rotated upwardly such that theproximal leg portion 202 a moves over a respective dimple 198 and thetapered tip 202 c moves into a staple forming depression 182 a of theanvil 182 to initiate deformation of the staple 186. When the proximalleg portion 202 a of each staple 186 moves over the plateau 230 andalong the second curved surface 228, the second curved surface 228 ofthe cam surface 222 a and 222 b fully deforms and disengages each staple186 from the cylindrical slot 208 of a respective notch 196. As shown inFIGS. 30 and 32, the proximal leg portion 202 a of each staple 186serves as a guide for an adjacent proximal staple 186 as the adjacentproximal staples 186 are cammed from the cartridge body 184. Thedistal-most staple 270 in each row of staples 186 is a dummy staple andis not fired from the cartridge body 184. The dummy staple 270 providesa guide surface for the adjacent proximal staple 186. Alternately, thedummy staple 270 may be replaced with guide grooves or dimples formed onthe cartridge body 184.

Referring to FIGS. 34-38, the tool assembly 114 can be articulated bymovement of the cartridge channels 140 a and 140 b in oppositedirections in relation to each other. As discussed above, the cartridgechannels 140 a (FIG. 3) and 140 b extend from the proximal body portion110 through the elongated shaft portion 112 to the tool assembly 114. Adistal end of each of the cartridge channels 140 a and 140 b isconnected to the pivot member 157 by a respective post 172 (FIG. 3A)which extends through the proximal openings 210 a of the cartridgechannel 140 a and 140 b. The proximal ends of the cartridge channels 140a and 140 b include cutouts 142 a and 142 b, respectively, which receivehook portions 120 a and 122 a of the articulation rods 120 and 122,respectively, to connect the articulation rods 120 and 122 to thecartridge channels 140 a and 140 b. The first and second articulationlinks 120 and 122 are slidably supported between the housing halves 116a and 116 b of the proximal body portion 110. The first articulationlink 120 has a distal end connected to the cartridge channel 140 a and aproximal end connected to an articulation assembly 300 (FIG. 1) of theactuating device 12 (FIG. 1). The articulation member 123 includes aC-shaped body 302 having spaced fingers 304 and 306 and a centralopening 308 (FIG. 35). The fingers 304 and 306 are received in cutouts310 formed in the distal end of first and second articulation links 120and 122. The central opening 308 receives a housing post 312 (FIG. 36)formed on housing half 116 b of the central body portion 110 such thatmovement of the first articulation link 120 in one direction asindicated by arrow “A” in FIG. 37 causes the articulation member 123 topivot about the housing post 312 to cause movement of the secondarticulation link 122 in a second direction as indicated by arrow “B” inFIG. 37.

In use, when the first articulation link 120 is moved by thearticulation assembly 300 in direction A, the cartridge channel 140 a,which is axially fixed to the first articulation link 120 by placementof hook portion 120 a in cutout 142 a (FIG. 3), is also moved indirection A. Movement of the first articulation link 120 in direction Aeffects pivotal movement of the articulation member 123 which causesmovement of the second articulation link 122 in the direction of arrowB. Movement of the second articulation link 122 in direction of arrow Bcauses movement of cartridge channel 140 b in the direction of arrow B.As discussed above, the distal ends of cartridge channels 140 a and 140b are connected to opposite sides of the pivot member 157. As thecartridge channels 140 a and 140 b are moved in opposite directions, thepivot member 157 is pivoted about the pivot pin 170 to pivot the toolassembly 114 in relation to shaft portion 112 such that the longitudinalaxis of the tool assembly 114 is offset from the longitudinal axis ofthe shaft portion 112. It is noted that the cartridge channels 140 a and140 b, the firing cams 138 a and 138 b and the distal drive members 136a and 136 b are all formed of a resilient material such as spring steelto facilitate movement about the axis of articulation to an articulatedposition.

Persons skilled in the art will understand that the devices and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary embodiments. It is envisioned thatthe elements and features illustrated or described in connection withone exemplary embodiment may be combined with the elements and featuresof another without departing from the scope of the present disclosure.As well, one skilled in the art will appreciate further features andadvantages of the disclosure based on the above-described embodiments.Accordingly, the disclosure is not to be limited by what has beenparticularly shown and described, except as indicated by the appendedclaims.

What is claimed is:
 1. A surgical stapler comprising: a shaft portionhaving a proximal end and a distal end; first and second cartridgechannels extending through the shaft portion, each of the first andsecond cartridge channels having a distal end defining a U-shapedmember; a pivot member pivotably coupled to the distal end of the shaftportion, the pivot member being fixedly coupled to the first cartridgechannel by a first post and fixedly coupled to the second cartridgechannel by a second post; and a tool assembly including an anvil and acartridge assembly, the cartridge assembly including a cartridge bodyand a plurality of staples, the cartridge body having a first legsupported in the U-shaped member of the first cartridge channel and asecond leg supported in the U-shaped member of the second cartridgechannel; wherein the first and second cartridge channels are movableaxially in opposite directions to pivot the pivot member in relation tothe shaft portion and effect articulation of the tool assembly.
 2. Thesurgical stapler according to claim 1, further including a firstarticulation link having a distal end secured to a proximal end of thefirst cartridge channel and a second articulation link secured to aproximal end of the second cartridge channel, the first and secondarticulation links being axially movable to effect axial movement of thefirst and second cartridge channels in relation to each other to pivotthe pivot member in relation to the shaft portion.
 3. The surgicalstapler according to claim 2, further including a pivotal articulationmember interconnecting the first articulation link to the secondarticulation link such that movement of the first articulation link inone direction effects movement of the second articulation link in anopposite direction.
 4. The surgical stapler according to claim 1,wherein the plurality of staples are rotatably supported in thecartridge assembly, and wherein the surgical stapler further comprises afirst firing cam and a second firing cam.
 5. The surgical stapleraccording to claim 4, wherein the staples have a shape of an open loop.6. The surgical stapler according to claim 5, wherein the staples havetwo legs.
 7. The surgical stapler according to claim 6, wherein thestaples have a backspan that is positioned in a notch in the cartridgeassembly.
 8. The surgical stapler according to claim 6, wherein movementof the first firing cam and the second firing cam rotates the staplesinto engagement with the anvil and deforms the legs of the staples intoa closed shape.
 9. A surgical stapling instrument comprising: a shaftportion having a proximal end and a distal end; a first cartridgechannel and a second cartridge channel extending through the shaftportion; a pivot member pivotably coupled to the distal end of the shaftportion, the pivot member being fixedly coupled to the first cartridgechannel by a first post and fixedly coupled to the second cartridgechannel by a second post; and a tool assembly including an anvil and acartridge assembly, the cartridge assembly including a cartridge bodyand a plurality of staples, the cartridge body having a first legsupported in the first cartridge channel and a second leg supported inthe second cartridge channel; wherein the first and second cartridgechannels are movable axially in opposite directions to pivot the pivotmember in relation to the shaft portion and effect articulation of thetool assembly.
 10. The surgical stapling instrument according to claim9, wherein each of the first and second cartridge channels have a distalend defining a U-shaped member.
 11. The surgical stapling instrumentaccording to claim 9, wherein the plurality of staples each have twolegs and a backspan.
 12. The surgical stapling instrument according toclaim 11, wherein the staples are rotatably supported in the cartridgeassembly for engagement with a first firing cam and a second firing cam.13. The surgical stapling instrument according to claim 9, furtherincluding a first articulation link having a distal end secured to aproximal end of the first cartridge channel and a second articulationlink secured to a proximal end of the second cartridge channel.